Tls outbound proxy problem

I’m working on my final project about implementing a solution of voice over ip in my faculty and everything is working fine I’ve created a lan Network i have an asterisk server 16. 5.1 installed on ubuntu 16.04 and 3 clients. the calls are working fine the srtp, acl,iptables. But when i add tls it doesn’t work on blink when i add the outbound proxy wich is the address of asterisk server the client doesn’t appear connected and the cli doesn’t give any error and when i remove the outbound proxy it connects. Need your help and thank you.